Introduction (1)

Watch this OK Go video and think about what your brain thinks is happening and what is actually happening in the scene.

What did you see? What did you see that was not there?

Was your perception influenced by features, like lines and color? Was there a back and forth between what your perceptual system believed and what was there in reality?

But how did our perceptual systems get tricked?

Throughout this blog you will begin to understand the perceptual mechanisms that make videos like this work.

Where to begin: Let’s start by talking about the difference between sensation and perception.

Sensation is the physiological process that occurs when light reaches our eyes. Perception, on the other hand, is the process of forming meaningful events from the information available in the environment.

Let’s learn some terms that will help you understand this distinction.

A distal stimulus is anything in the world that is illuminated by a light source, such as OK GO (see below).

Ok GO and the eye

A proximal stimulus is an item that interacts with the receptors in our eyes. In this example, it is the upside down OK GO. Due to the nature of the lenses, when the light is projected through it the image gets flipped. The light that actually hits our receptors is upside down.

However! Our perception, or our subjective experience, of OK GO is right side up! How can that be?? If the information that makes it to our eyes is upside down how is it that we perceive the information in the correct orientation?

To start to get a handle on this question, let’s talk about the differences between the stimuli more. What are the differences between distal and proximal stimuli?

The distal stimulus is constrained by physical properties such as size.

For example, when the members of OK GO are moving around they stay the same height – meaning that the properties of distal stimuli remain constant.

OK GO and Eye

However, when OK GO gets farther way from your eyes the image that is sent to the receptors is smaller. The actual light that is hitting your retina changes in size. Yet, we perceive that OK GO is the same size, just moving closer and farther.

Another example is with shape.

Door and eye

The shape of something like a door is always physically the same (distal stimuli). But the shape of the light that reaches your eyes (proximal stimuli) changes. Yet your perception of the shape of the door remains the same.

These examples illustrate the concept of constancy in neuroscience – the magic behind how the world interacts with our eyes, brain, and full body to magically make us believe we see what we see.

These are the types of problems that we will be exploring together in this blog.


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